The Are Multiple Sources of Truth for the gRPC interface

[zancas]

In particular the following files all define the CompactBlock type:

(1) ECC Rust Client LIbrary: zcash_client_backed

(2) ECC Go Zcashd Proxy: lightwalletd

(3) Zingolabs Rust Contract SDK: zingolib

Many sources of truth for the network interface eliminates one of the motivating benefits of a protobuf architecture, which is that the client and server are guaranteed to agree on an interface because they derive it from the same source!

Potential Solution:

• some repository contains the canonical specs (.protos) dependents reference those spec files. It seems obvious that the canonical spec files should be in lightwalletd.